“(6) …where- (a) any goods are acquired from another member State in a case which corresponds, in relation to another member State, to the case specified in relation to the United Kingdom in subsection (1) above; and (b) the person who acquires the goods is registered under this Act and would be the intermediate supplier in relation to that corresponding case, the supply to him of those goods and the supply by him of those goods to the person who would be the customer in that corresponding case shall both be disregarded for the purposes of this Act …”